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<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div></div>
    <script>
        console.log(location.search);//?uname=123
        //1.先去掉? substr('起始的位置',截取几个字符);
        var params=location.search.substr(1);//uname=123
        console.log(params);
        //2.利用等号分割为数组
        var arr=params.split('=');
        console.log(arr);
        var div=document.querySelector('div');
        //3.把数据写入div
        div.innerHTML=arr[1];
    </script>
</body>
</html>